No incoming message sound when locked - iPhone 6, iOS 8

RESOLVED - I have been having this issue too for several years now. For no specific reasons, I would regularly observe that there was no more text message sound notification (silent switch and Do not Disturb functions were not activated). I would clear the bug by simply rebooting my phone (switch OFF-ON). Today, I tried again to determine the cause of this erractic behavior and I manage to replicate the bug. I can confirm that it is related to the bluetooth. I have a Denon sound system that I have equipped with a Bose bluetooth adapter (optical connection). Earlier this week, I connected to my sound system to listen to Sirius music from an App on my iphone 6. Since then, there was no more text message sound notification. Even if my sound system is turned off and the Sirius App is closed, the phone remained connected to the Bose Bluetooth adaptor. I switched OFF-ON the iphone bluetooth and voila! The Bose bluetooth adaptor was longer connected to the phone and the sound notification of text message went back to normal. I tested one more time to confirm and validated that the same bug occured (no sound), disconnected the bose adaptor from my iphone bluetooth and the notification sound was back.

Could it be that your connected to a Bluetooth or other wireless device that is getting the sound signal? Just a thought. It happened to me when I was near my vehicle which was still running and was connected via Bluetooth.

Good luck!

TRY THIS ITS WORKED IN MY PHONE.......FIRST OPEN ANY SMS ON THE TOP RIGHT SIDEYOU SAW A ICON TAP IT A NEW WINDOW OPEN SCROL UP YOU SAW ”HIDE ALRETS” IF ITS TURN ON (green) TURN IT OFF I HOPE YOUR PEOB SOLVE........I SEND SOME DEMO PICS........THANKS

I think this may have solved my problem - I was connected to a bluetooth device which was connected to a Bose radio. Not sure how long that has been on, but after disconnecting it I immediately had sound again. I hope that was it once and for all.

syedaisar:

Thanks, found the "hide alerts" active when pressing the info button. How it got that way is a mystery.

All fixed at the moment.

Turned of my Apple Watch 3 and they work. Haven’t found the complete fix yet. Watch back on and they don’t work.

Yes! This is exactly what my issue was! Once I clicked the Do not Disturb, I saw it was ON, turned it off and walla! Tones!

I started having this problem in iOS 11 and tried ever other fix because I thought that the headphone jack fix was a little Bizzarre. BUT...ypurs was the one that worked...Thank You!!!

My mom and I both have this issue, I have a 6plus and she has a 7. I just tried your recommendation and oh my gosh it worked. I'll try her tomorrow. Thank you!

Me too!

Spot on sir , you are a genius , the only thing that has worked for (Bluetooth ) unbelievable

It worked for my IPhone 8 Plus .

Thank you .

Did not help my SE still no sounds. This just started today

THANK YOU!!!!

Same problem here. I tried resetting my iPhone 8 Plus , it was ok for couple days, then back to same problem.